The present invention relates to a hoisting winch, in particular to a hoisting gear winch, having a hoisting drum whose winding region is bounded by two lateral flanged wheels, wherein at least one further flanged wheel is provided between the lateral flanged wheels for dividing the winding region into at least two part winding regions, wherein the cable can be guided beyond the named further flanged wheel into the at least two part winding regions.
Winding problems typically occur in hoisting winches when the hoisting drum has a very large number of turns next to one another and the cable is to be wound in a plurality of layers over one another. The problem is in particular intensified in this respect when the cable is to be wound up without any or with only a little cable preload. If higher cable tension forces abruptly act on a more or less loosely wound cable package such as can occur, for example, during demolition work or dismantling work, the loose winding package can be displaced, with the cable tending to cut in between winding layers disposed thereunder. This problem also occurs in an intensified manner in applications in the deep-sea sector since here cable lengths often have to be wound up and unwound over several thousand meters. A cable which has been severely cut in results in the worst case in the destruction of the cable so that it has to be replaced. There is furthermore the risk that the hoisting procedure can no longer be completed and complex auxiliary measures have to be initiated.
The background of this possible cutting in of a cable between cable layers disposed thereunder is in this respect also the fact that thickness tolerances of the cable to be wound up have to be considered for the windings of the cable on the hoisting drum. The pitch on the hoisting drum has to be matched to the possible cable tolerances, with a certain play being necessary between the cable to be wound up and the winch pitch so that the cable sections have room next to one another on winding up, with this play being decisively influenced by the cable thickness tolerance, the hoisting winch pitch tolerance and the nominal play. With commercial cables, the tolerance of the cable diameter amounts to approximately 2-4% of the nominal diameter so that the pitch on the hoisting drum has to consider approximately 5% of the nominal diameter of the cable. Tighter tolerance widths are admittedly offered on the market, but are expensive and are not available everywhere. Accordingly, the cable gap between the windings can vary in dependence on the tolerance of the cable diameter, with the cable gaps adding up over the windings so that it can occur with the aforesaid tolerance ranges and the cable thicknesses customary for hoisting gear with a winding number of around 40 that the maximum added up gap dimension may exceed the cable thickness. Accordingly, it can occur due to a cable tightly tensioned in the next winding layer that the layers disposed thereunder are displaced or the named cable can cut into between two winding sections disposed thereunder.
Furthermore, the named winding problems are also influenced by the run-off angle or the run-in angle of the cable with respect to the longitudinal drum axis. The more slanted the cable is on running off the hoisting winch or on running onto the hoisting winch, the greater the tendency to transverse displacements and winding problems.
To avoid the named problems or to alleviate this problem, a hoisting drum having a very large drum diameter is typically selected for very large cable lengths in order nevertheless to be able to wind up and unwind large cable lengths with a limited number of windings next to one another. However, this produces hoisting drums which are heavy in construction and relatively expensive in manufacture. In addition, with large drum diameters, high torques necessarily arise in the winch transmission due to the cable tension and the drum radius as well as the lever arm derived therefrom which result in corresponding loads and wear.
Document DE 20 2005 011 277 U1 proposes a hoisting winch of the initially named kind in which the winding region is divided into a plurality of part winding regions in which the cable is successively wound up. A further flanged wheel which divides the winding region into two part winding regions is arranged approximately centrally between the lateral flanged wheels which bound the total winding region in a manner known per se. The cable can be led beyond the flanged wheel via a spiral cable guiding channel at the said further flanged wheel to wind up the cable in the second part winding region after winding the first part winding region.